Using the procedure and apparatus according to the present invention, it will thus be possible to manufacture both an implant body and a tool part or parts employed in the production of the implant body. Production of a tool part for an implant body is relevant to the production of tooth sockets whose inner configuration must be adaptable with extreme accuracy to the tooth remains in question. In this case, electro-erosion is employed, in which it is necessary that the outer configuration of the tool part coincide with extreme accuracy (100 parts of 1 mm) with the outer configuration of each respective tooth remain. In such instance, it should also be noted that the tool parts (which, in the case of production of tooth crowns, consist of electrodes of graphite) are exposed to wear (primarily frontal wear) during the electro-erosion. The production of a tool part or parts is also relevant in the procedure for producing ceramic bodies which are linearly enlarged in relation to the replacement or support part and reduced in size by hard sintering in order to conform with extreme accuracy to the size of the replacement or the support part.
It is previously known in this art to transfer a configuration from a model to the implant body or the tool part herefor. By way of example, reference is made to the tracer milling cutter according to PCT application SE87/00194 WO 87/06451). This tracer milling cutter employs a sensing needle which senses the configuration of the model in question, and hydraulically operating servo devices which transfer the movements sensed by the needle to the processing tools which form the blank. The above-mentioned publication discloses in general terms that it is possible to alternatively employ a tracer milling cutter which operates with electric servo devices.
It is also previously known in the art to propose, in the above type of tracer milling cutter, an apparatus which makes possible enlargement/reduction of the form of a sensed model.
It is also well known in the art to employ electro-erosion in the production of, for instance, tooth crowns/tooth sockets.
The prior art equipment imparts an extremely high degree of accuracy to the produced implant bodies which are usually characterized by unique, individual outer and/or inner configurations.
It is also previously known in the art to attempt to cast the individually shaped bodies. Casting of such bodies provides inferior surfaces and requires individually designed and shaped tools. This mode of approach must be regarded as inferior to the principles according to the present invention which are based on cutting or some other type of forming machining.
In the production of implant bodies, there is a general need to be able to rationalize production of such implant bodies which must then be capable of displaying individually distinguished and also complex inner and/or outer configurations. The prior art equipment and procedures for this purpose are relatively slow, and in certain cases require the production of bodies of advanced design which cannot be achieved, or which can be achieved only with difficulty, using today's prior art equipment.
There is also a need in the art for increase in access to biocompatible material in connection with replacements and implant of support bodies in the human body. As a rule, such material is difficult to work with and must be capable of being employed in cost-effective and manufacture-efficient procedures and apparatus for the production of organic forms.
Hence, there is a need in the art to technically simplify the machines employed and their associated equipment, while still being able to utilize these more generally in the production of implant bodies. In this instance, the purely hydraulically operating equipment suffers from limitations and requires a relatively large machine park if all-round production of individual bodies and electro-erosion tools for these were to be satisfied. Different machines are thus required for cases with or without enlargement/reduction function. Production of tooth sockets and tool parts for these also requires other machine, since the tool parts must be designed with a wear allowance. The production of, for instance, complete teeth requires an additional machine variant. Those cases in which it is desired to build onto the produced form in relation to the form of the sensed model (as may be relevant in the production of a complete tooth/tooth part), would theoretically require one kind of machine for each superstructure operation, which, in principle, would be impossible to satisfy with present-day hydraulically operated tracer milling cutters.
The ideal is thus to be able to utilize a single machine in which it is possible to manufacture the desired implant body in response to controls which may be simply varied. In this instance, it must be possible to enter information on the configuration of the body in question either manually or automatically by read-off, copying, and the like, whereafter the control equipment generates, in response to such information, the correct control signals to the machine which, in response to the generated control signals, produces the usually individually shaped body.
The hydraulically operating tracer milling cutter also suffers from drawbacks of not being capable of working sufficiently rapidly. The sensing needle must abut against the model with a certain force, the so-called reaction force. The model is usually made of a plaster of Paris or other soft material, which limits the magnitude of the reaction force. On the other hand, the reaction force must be increased with increasing working speed in order for the needle to be capable of following the contour, and the above-mentioned limitation in working speed will be readily perceived herefrom. In addition, the needle must be provided with a rounded tip (not a spiculated tip) in order for the model/plaster material not to be destroyed by the needle. This limits sensing accuracy in complicated shapes and it will readily be perceived that implant bodies of complex individual shapes cannot, for this reason, be manufactured with a sufficient degree of accuracy. The possibility of producing the implant body with complex shapes is also restricted by the fact that the axes of rotation of the rotary units cannot work above the rotary shaft of the blank because the above-mentioned axes of rotation are inclined at an angle in relation to each other. Such angular setting affords a number of advantages which it would be difficult to forego in the above-mentioned prior art tracer milling cutter.
The procedure and the apparatus according to the present invention are also intended to make possible the production of cavities in relevant blanks with a high degree of accuracy.